Fossil fuels, such as coal, oil, and natural gas are non-renewable energy sources and their ever-increasing consumption leads to excessive emission of greenhouse gases, and in particular carbon dioxide (CO2). To mitigate negative consequences of fossil fuel use, methods for reduction of carbon emission have been implemented, but with marginal success. Concern over fossil fuel use has also led to global development and implementation of renewable energy sources over the past decades. Renewable energy sources such as biomass are increasingly harvested to generate energy and raw materials (e.g., via gasification), but substantial technical issues remain due to low quality products and excess ash formation.
Co-electrolysis of steam and carbon dioxide by use of solid oxide electrolysis cells (SOECs) is a promising method that can efficiently transform carbon dioxide and water into syngas (a mixture of H2 and CO), which can subsequently be used as feedstock for chemical synthesis, for instance through the well-established Fischer-Tropsch (F-T) process to produce liquid hydrocarbons. Liquid hydrocarbons are often preferred to syngas as feedstock materials as they can be more easily and more safely stored and transported using existing infrastructure.
Unfortunately, there are still major challenges for large scale deployment of SOECs in hydrocarbon generation. One principal challenge is that syngas production via co-electrolysis is a high temperature process (normally from about 600° C. to about 1000° C.) and integration of this high temperature process with lower temperature syngas processing techniques such as F-T processing (normally from about 200° C. to about 500° C.) presents significant technical challenges.
What are needed in the art are methods and systems that can successfully integrate solid oxide cell co-electrolysis processes with syngas utilization processes to improve use of renewable energy sources and decrease carbon emissions. Such integration can not only provide scalable energy storage, but can also be utilized to produce chemicals or fuel by use of recycled CO2.